I'm not quite sure, but I rather think in this case it was not about fixing 'truth', but more like a ready remedy for a huge feeling of guilt (also, as it was often claimed, consideration for the victims, who should not be told to their face that their sufferings are ficticious), and the wish not to be associated with the Nazi ideology any longer.

OF COURSE, this makes those topics more powerful (as it has been for putting 'Mein Kampf' on the index, which by itself is nowehere near a brilliant book), but this is the very own German trauma, beware if you touch it.

Interesting cases related to that are the trial of Althans (who starred a movie going to Auschwitz and claiming there was no Holocaust (right to the victim's faces, actually), but where a young Israeli tells him the right of things (beautiful demonstration of how freedom of speech works both ways)), and the very recent opening of the new Jewish cultural centre in Munich (target to an uncovered plot to bomb the site), where a protest march of the extreme right to disturb the ceremony was banned (people tried to schedule it under a sham issue).

Now, this is really something to give people headaches. Do you want to have rioting neo-Nazis in your ceremony? Certainly not. Given they just counter-demonstrated in a peaceful way, should that be allowed? But how can you really tell in advance. Experience, that is what people claim.